1. Field of the Invention
The present invention relates to a storage device having a lock system for the access mechanism on which heads are mounted, and a method for locking the access mechanism. More particularly, the invention relates to a storage device capable of locking the access mechanism linearly driven above different tracks on a recording medium, and a method of locking this access mechanism.
2. Description of the Related Art
There has been developed the filing device adapted to use a recording medium or floppy disk of 3.5 inches, for example, having extremely high density tracks. In the case where data is recorded on and reproduced from this recording medium, it is needed that the recording and reproducing means such as the magnetic head is moved with extremely high accuracy and at high speed and is correctly positioned relative to a destination track on the disk. To meet this need, there has been developed a filing device in which the carriage mounting the head is moved not by the step motor but by the linear actuator, because the linear actuator can more correctly position the head relative to a destination position. An example of this linear actuator for moving the head is disclosed in U.S. Pat. No. 4,745,503 which has been issued to the assignee of the present invention.
The U.S. Patent discloses a voice coil motor, which serves as the linear actuator, including a permanent magnet having an E-shaped yoke whose center portion is extended in the access direction of the head relative to the disk, a motor coil attached onto the center portion of the yoke and movable in the access direction of the head, and a flattened box-like carriage in which the motor coil is housed and fixed and on which the recording and reproducing head is mounted.
This voice coil motor is generally shaped flat because its carriage is made like a flat box. This enables the disk drive device to be made flat and applied to various fields.
Further, other linear actuators intended to be used for the disk drive device are disclosed in International Patent Application (Disclosure No. WO/83/04130) and preliminarily-opened Japanese Patent Application Sho 58-161176. Both of these are intended to provide a small-sized and high quality linear actuator and they are satisfactory to some extent.
In the case of the above-mentioned voice coil motors which serve as the actuator, however, the motor coil for moving the carriage is not excited when the head is not moved o head-mounted carriage is not in operation. The carriage is thus allowed to freely move in the direction of its gaining access to the floppy disk. This free movement of the carriage is preferable to work at high speed while the filing device is in operation.
When the device is not in operation, however, the free movement of the carriage must be prevented. In the case where the device is carried to another place, at the time when the device is not in operation, the carriage moves, together with the device, to strike against its stoppers, so that the head or head-mounted carriage can be broken at worst. Particularly in the case of the portable electronic machine using such device, the free movement of the carriage must be prevented because this machine is usually under carriage.